Rockwell Automation 1756-IH16ISOE ControlLogix Sequence of Events Module User Manual

Page 146

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Publication 1756-UM528A-EN-P - April 2004

D-12 Using Module Tags

O.UCTTime[2]

DINT [2]

These tags are used to configure the Sequence of Events module to send timestamps to
the controller in UCT format. In this case, you must copy a pair of timestamp values from
the 1756HP-GPS module (one in UCT format and the other a corresponding CST format
value) to these tags.

When these tags are nonzero numbers, the Sequence of Events module converts
timestamps from CST format to UCT format before sending them to the controller.
Additionally, I.ReturningUCTTime = 1.

Typically, the following events occur:

• A 1756HP-GPS module produces CST/UCT Time pairs that are sent to

the controller.

• The controller copies the pairs to the Sequence of Events module every pulse per

second (PPS). (We recommend you copy the pairs every PPS.)

• The Sequence of Events module uses the streams of pairs to calculate UCT

timestamps for input data including the use of calculating drift between the
clocks.

If these tags = 0, the Sequence of Events module sends timestamps in CST format and
I.ReturningUCTTime = 0.

O.CSTTime[2]

DINT [2]

Table D.7 Output Tags in FIFO Mode

Tag name:

Type:

Description:

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